The present invention relates generally to mattress construction. More particularly, the present invention relates to a mattress including structure that minimizes a drum effect as well as a construction approach lending itself to the use of superior materials without significantly increasing the cost of making a luxury mattress.
In conventional mattresses for use as beds, it has been recognized that certain mattresses include structure creating an undesirable drum effect such that the sleeper does not benefit from mattress substructure but rather, sleeps on a drum-like surface. It has also been recognized that it is important to provide a mattress made from high quality raw materials so that the mattress maintains consistent resiliency across a sleeping surface and the tendency for the creation of permanent depressions is minimized.
Due to wear and tear, the surface of a conventional mattress might sag, shift, lose its form, etc. A sleeper lying on the mattress might inadvertently roll off the mattress due to the lack of support at the sagging edge. To overcome such problems, there have been many approaches to mattress design.
Most improvements in the area of mattress design focus on the innerspring unit of the mattress. The innerspring unit is usually made from a plurality of spring coils arranged side-by-side in a rectangular matrix. A border made of metal wires encircling both the upper and lower surfaces frame the innerspring. The plurality of helical spring coils are positioned in a spaced apart relationship within the innerspring unit to provide the internal support for the mattress.
Some examples of mattresses using a modified innerspring unit include a pair of ridges formed on a sheet of elastomeric material that covers both sides of an innerspring unit. The elastomeric material is attached to the innersprings. Other approaches involve a border stabilizing and reinforcing member for use in mattresses. A plurality of rhomboid-shaped members of resilient material can be placed in the innerspring unit of a mattress between adjacent rows of springs. When placed as a beam between the springs, the rhomboid-shaped members improve firmness of the mattress.
Another approach involves a mattress border construction including a foam rail sleeve encasing a single row of coiled springs so that the top, bottom, and sides of the row of springs are surrounded by foam. Essentially, the coiled springs encased in the foam sleeve reinforce the border or edges of the innerspring unit giving it strength.
Moreover, in yet other approaches a mattress topper pad consisting of sheets of foam padding are provided wherein the soft foam is located in the middle of the sheet and the hard foam is located at the periphery or edges. Two or three of these sheets are laid on top of the innerspring unit.
Other conventional approaches involve including a bed guard comprising at least one elongated bolster assembled on top of a conventional mattress held in a position along one edge of the bed. A plurality of bolsters may be used on each edge of the bed for additional roll-off protection. Another design suggests using an array of pockets in which cylindrically shaped foam members are inserted to define a retainer structure enclosing a sleeping area on the mattress. Another conventional mattress design suggests using elastic foamed block inserts positioned into the void spaces left in the innerspring assembly at the periphery of the mattress. Other designs include a mattress topper pad and border stabilizer means for mattress innerspring units. The topper pad portion overlies the top or bottom of the coil innerspring unit while the border stabilizer portion is inserted between at least one convolution of each coil on the outside row of the coil innerspring unit to stiffen the spring action of the coils.
Certain of the conventional designs do not include a quilted, pillow top mattress. Such a mattress does not permit a top cover to move in from the edges of the mattress and therefore creates a drum effect. Consequently, the construction of the mattress works against itself in that a sleeper does not completely benefit from mattress substructure providing comfort and response to weight distribution (such as springs), but rather the sleeper lies upon a drum-like surface.
Further, conventional pillow-top mattresses typically include a gusset extending around a perimeter of the mattress. The gusset acts like a hinge which therefore allows the mattress cover to draw up about a sleeper. However, such conventional pillow-top mattresses require an extra layer of fabric between the mattress inner spring unit and the top upholstery which creates a drum effect within the body of the mattress. Although the drum effect is moved deeper within the mattress as compared to other conventional non-pillow top mattresses, the sleeper nevertheless does not completely benefit from the full comfort and functionality of the inner spring assembly. Another disadvantage of these conventional pillow-top mattresses is that they have become very thick (15-20 inches) in order to overcome the internal drum-like structure which makes it more difficult to find and fit sheets. Also, there exists a greater propensity for sagging mattresses and mattresses developing depressions.
Moreover, the multiple layers of upholstery or other materials included to create a barrier between bed springs and a sleeping surface adds to the material cost of a mattress. To offset material costs, manufacturers may select lower quality raw materials which do not stand the test of time. The undesirable permanent depressions can more readily form in the sleeping surface produced from the cheaper materials, which thus limits the life of a bed or at the very least, effects the long-term comfort of the bed.
Accordingly, there is a need for a mattress which both addresses the drum effect problem as well as provides a comfortable mattress having a long useful life. The present invention satisfies these and other needs.